The sampling design is built to capture a representative sample of Facebook users who were 18 or older and predicted to be in the disaster region of the Green Wattle Creek and Cudlee Creek fires (Figure REF ). Through a combination of app-based user targeting (e.g. in Australia) and survey gatekeeping (e.g. Q2) we are able to isolate these respondents. Specifically, we take all Facebook users who have been identified to be in the region based on their city location and age. We also include users as identified by their Location History as reported in Facebook's Data for Good program Displacement Map. We are then able employ rejection sampling to limit our final respondent set to only included the target population. This method is very general and will provide a random sample of users in the two regions [1]}. We are able to adjust for survey non-response through the application of survey weights (see Section REF ). All users were asked for informed consent to survey and all questions allowed the respondent to not respond (See Question 1). No participants were compensated in any way for their participation.
